Apparatus for the preparation of parisons

ABSTRACT

Method and apparatus for the preparation of oriented hollow objects of moldable organic plastic material by providing a parison on a first blow core, expanding said parison into an intermediate shape, as by pre-expanding it, transferring said pre-expanded parison to a second blow core, finally extending and expanding said parison to form said hollow object in finished shape.

This is a division of application Ser. No. 473,580, filed May 28, 1974,now U.S. Pat. No. 3,966,378.

BACKGROUND OF THE INVENTION

This invention relates to the art of blow molding articles of organicplastic material from a parison and has for its principal object theprovision of improved, oriented hollow articles and a method andapparatus for obtaining same.

The art teaches various methods and apparatus for obtaining blow moldedarticles of organic plastic material from a parison, such as in U.S.Pat. No. 3,349,155 and Re. No. 27,104. Generally, these methods arechracterized by forming a parison in a parison mold on a blow core,placing said formed parison and blow core into a blow mold and expandingsaid parison in the blow mold by means of fluid pressure.

Naturally, the blowing procedure inherently produces orientation in theplastic due to expansion in a radial direction; however, it is highlydesirable to produce orientation in the axial direction as well.Heretofore, this has been done by reheating the parison and, beforeblowing, axially orienting the parison, such as by stretching.

Such known methods are subject to disadvantageous aspects. A particulardisadvantage has been the difficulty of maintaining uniform wallthickness. Obviously, control of wall thickness distribution is quiteimportant. Other difficulties include insufficient control of theparison dimensions and degree of orientation and time consuming andinconvenient operations.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method is provided for thepreparation of hollow articles oriented in the axial, radial andtangential directions from moldable organic plastic material whichcomprises providing a parison on a first blow core, partially expandingsaid parison so as to free it from surface contact with said blow coreand to convert it to a shape intermediate between that of the parisonand that of the finished article, transferring said parison to a secondblow core, axially extending and finally expanding said pre-expandedparison to form said hollow object.

If it is desired to produce a multi-layered parison, the blow core mayfirst be provided with a layer of one plastic, and a subsequent layermay then be pressure molded therearound, in accordance with my U.S. Pat.Nos. 3,349,155, 3,717,544 and 3,719,735. While the general descriptionthat follows refers simply to parisons, it is understood that the methodand apparatus of the present invention are applicable to multi-layeredas well as single-layered parisons. In this regard, further descriptionis provided below for various such modifications within the scope ofthis invention.

The apparatus of the present invention includes a first blow core, meansfor providing a parison thereon, a pre-forming mold for partiallyexpanding and, if desired, partially extending said parison of saidfirst core in an axial direction, means for so expanding and extendingsaid parison on said first core, means for separating said first corefrom said pre-forming mold and the pre-formed parison contained therein,a second blow core in spaced relationship to said first core, means fortransferring said pre-formed parison to said second core, means foraxially extending said preformed parison, a second mold in spacedrelationship to said pre-forming mold, and means for fully expanding thepartially expanded and axially extended parison in said second mold.

It can be readily seen that the hollow article of the present inventionis characterized by highly improved properties by virtue of the factthat the walls thereof are controllably oriented in the axial, radialand tangential directions. It is known that orientation substantiallyimproves the significant properties of plastics, as clarity, impactresistance, strength, resistance to permeation, etc. Among the plasticsthat can be so improved are polystyrene, polyvinyl chloride,polyolefins, as polyethylene and polypropylene, polyesters, polyamides,acrylics, acrylonitrile and methacrylonitrile polymers. The controlledorientation in the axial, radial and tangential directions, whichcharacterizes the article of the present invention, therefore representsa significant advantage, and an advantage which is obtained in a simpleand expeditious manner.

Accordingly, it is a principal object of the present invention toprovide a method for the preparation of hollow articles from moldableorganic plastic material which are characterized by being controllablyoriented in the axial, radial and tangential directions.

It is a further object of the present invention to provide a method asaforesaid which yields products possessing uniform wall thickness.

It is yet a further object of the present invention to provide anapparatus for use in the method as aforesaid which enables the severalsteps to be conducted continuously and concurrently.

Other objects and advantages will be apparent to those skilled in theart from the description which follows with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation, partly in section illustrating an apparatus inaccordance with this invention.

FIG. 2A and 2B are views similar to FIG. 1 with additional portions inphantom showing a sequence of operations according to an embodiment ofthe method of this invention.

FIG. 3 is an elevated view, partly in section illustrating an alternateapparatus for providing a parison according to the method of thisinvention.

FIG. 4 is a view similar to FIG. 1 which shows an apparatus for thepreparation of lined and composite parisons.

FIGS. 5A and 5B show an apparatus and sequence of steps illustrating analternate preparation of lined and composite parisons.

FIG. 6 is a schematic sectional view of an alternate embodiment of thisinvention.

FIGS. 7A, 7B and 7C illustrate a sequence of steps associated with theembodiment of FIG. 6.

FIG. 8 shows rotary indexing removal fingers employed in accordance withthis invention.

FIG. 9 is a sectional view showing rotary indexing finishing molds inaccordance with an alternate embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in more detail, FIGS. 1, 2A and 2B illustratean apparatus in accordance with one embodiment of the present invention.In this embodiment, the parison is provided by an injection moldingprocess, however, the invention is not limited thereto and includesother known molding processes that are capable of producing parisonssuch as compression molding, casting, extrusion with or withoutsecondary operation, and the like. FIG. 1 depicts a parison die 10,having outer walls 11 which may be separable, depending upon the shapeof the parison and which are adapted to form the outer surface of theparison, and having an end wall 12 shaped to form the end wall of theparison. The end wall 12 of the parison die has an injection opening 13registering with an injection nozzle 14 through which the organicplastic material is injected into the parison die. The parison die 10 isshown as split for convenience in opening to release the formed parison,however, it should be understood that the invention is not limitedthereto, as one-piece dies having suitable release mechanisms known inthe art are encompassed herein.

As indicated hereinabove, the plastics contemplated in accordance withthe present invention are the moldable organic plastic materials whoseproperties are improved by orientation, such as the polyolefins,polyethylene, polypropylene and copolymers thereof, polyvinyl chloride,polystyrene, acrylonitrile, methacrylonitrile, polyvinylidene chloride,polycarbonates, polyesters, polyamides, etc.

The formation of the parison in accordance with the embodimentillustrated in FIGS. 1, 2A and 2B takes place after a first blow core 15illustrated in FIG. 1, and set forth in phantom in FIG. 2A, and die 10are brought into engagement. Upon completion of injection through nozzle14, a parison 16 having substantially the configuration represented inFIG. 2A, is formed.

Blow core 15 encompasses an axially extensible portion 17 and provides aside wall and an end 18 for the formation with walls 11 and 12 ofparison die 10, of a die cavity in which the parison is formed. Blowcore 15 is carried by platen 19. This assembly further includes neckmold 20 which engages the parison while the latter is on blow core 15after disengagement from parison die 10. Neck mold 20 may be split andopened into two portions by suitable mechanical means, not shown, torelease the parison, or, if the configuration of the neck permits, maybe of one-piece construction and, thus, removable from the parison as aunit. In the embodiment illustrated in FIGS. 1, 2A and 2B, neck mold 20possesses threads which define a threaded opening in the final moldedobject.

Upon separation of the parison die 10 and the blow core 15 bearingparison 16, the latter assumes the position depicted in FIG. 1 and shownin phantom in FIG. 2B. Mold assembly 21 which comprises a pre-formingmold or pre-blow mold 22 and a second blow mold or finish mold 23, andblow core 15 are brought into alignment so as to juxtapose pre-blow mold22 and parison 16, illustrated, as noted earlier, in phantom in FIG. 2B.Pre-blow mold 22 and finish mold 23 are maintained in integral spacedrelationship by connecting member 24, and are arranged forreciprocation, for example, by means of hydraulic cylinder 25 which isillustrated in FIG. 1 as connected to finish mold 23 by the attachmentlabeled 26 thereon. The assembly may be supported for traverse betweenthe position suggested in FIGS. 2A and 2B, respectively, by conventionalmeans, such as tie bars or rails, not shown herein. Assembly 21, asdescribed above, is merely illustrative of one embodiment of thisinvention and is capable of modifications in design and operation, aswill be illustrated further on.

Referring now to FIG. 2B, upon the alignment of pre-blow mold 22 andcore 15 bearing parison 16, as noted earlier, blow core 15 and parison16 are then placed within pre-blow mold 22, for example, in the mannerindicated in the figure. Other means of engaging parisons and blow moldsmay be used and are well known, such as those disclosed in U.S. Pat.Nos. 2,853, 736 and 2,974,362. The parison is then partially expandedinto pre-blow mold 22, whose temperature may be controlled byconventional means, not shown, to optimize the parison temperature forsubsequent operations. Also, the parison is thereby freed from blow core15. As is illustrated in the figures, expansion is conventionallyachieved by the provision of fluid under pressure through passages 27provided within blow core 15 for that purpose. Axial extension of theparison may also be effected, if desired, after it is freed from theblow core, as above, by means of extensible portion 17 of blow core 15.The purpose of this step is to adjust the temperature of the parison foroptimum conditions during orientation and to avoid difficultiesheretofore encountered during axially extending the parison while insurface contact with the blow core. For example, if the parison isaxially extended while in surface contact with the blow core it tends tothin out unacceptably in localized regions due to the constraint causedby friction against the walls of the blow core. FIG. 2B illustrates theextent of expansion, as the perimeter of the unexpanded parison 16 isrepresented in phantom and the pre-expanded parison resulting from theexertion of fluid pressure is labeled 29. While axial extension is notshown at this stage, it is noted that such extension may be effected bymeans of extensible portion 17 of blow core 15.

After completion of the partial expansion, or pre-expansion of theparison, pre-blow mold 22 and blow core 15 are separated, andpre-expanded parison 29 is retained by pre-blow mold 22. As notedearlier, disengagement of parison 29 from blow core 15 may requireeither the opening or other removal of neck mold 20. Blow core 15 isthen returned to the starting position as illustrated in FIG. 1, andmold assembly 21 including pre-blow mold 22 containing pre-expandedparison 29 is shifted laterally into the position illustrated in FIGS. 1and 2A.

Parison 29 which is retained within pre-mold 22, is transferred to asecond blow core 30 for the final forming sequence. Blow core 30 issituated in the same spaced relationship to blow core 15 as existsbetween pre-mold 22 and finish mold 23, to enable both cores to engage arespective mold when core 15 is aligned with mold 22. This facilitatesthe concurrent pursuit of both the pre-forming and final formingprocesses with separate parisons. Further, and with regard to thetransfer of pre-expanded parison 29 to core 30, it should be noted thatparison die 10 is spaced from pre-mold 22, as illustrated in FIGS. 1 and2A, so that core 15 may engage with die 10 to form another parison whilecore 30 engages with pre-mold 22. The ability to concurrently conductthe various operations of the process outlined herein comprises one ofthe notable advantages of the invention. The simultaneous formation,preexpansion, or final expansion and finished article removal of aplurality of parts is envisioned, as the apparatus illustrated in theaccompanying figures can be further modified to provide additionalintermediate molds and cores, such as mold 22 and core 30. If a largevolume operation is desired, then a multiplicity of mold cavities andcores will be employed at each operating station, as is customary in theart.

As stated above, parison 29 is transferred to blow core 30 for furtherprocessing. Core 30 includes a transfer, stretch and blow assembly whichis carried by platen 31 and which comprises a mandrel extension 32 whichis reciprocable together with core 30 as indicated by the arrow in FIG.1 to axially extend the pre-expanded parison 29. An actuating means isshown which comprises a push rod 34 which engages mandrel 32, and whichis connected to a piston 35 housed within a cylinder 36 which may, forexample, be responsive to hydraulic pressure exerted by a pump, notshown. Such actuating means is merely illustrative of one manner ofoperation, as other actuating means known in the art can be employedherein.

A fluid passageway 38 is provided and extends radially, usually at theend surface of the core 30 that is attached to mandrel 32, in the mannerknown in the art for the construction of blow cores. Fluid passageway 38also connects to a source of fluid under pressure, not shown.Accordingly, fluid may enter the space inside pre-expanded parison 29during final expansion, discussed hereinafter.

A neck mold 39 is provided which is carried by platen 31 and cooperateswith sleeve portion 37 of the core to define the neck of the parison.Neck mold 39 is in all respects identical to neck mold 20, and maylikewise be modified in the manner suggested earlier for the latter. Infact, the assemblies comprising cores 15 and 30 are usually identical,except for obvious dimensional differences.

Referring to FIG. 2A, the transfer of parison 29 is conducted by theaxial extension of blow core 30 into engagement with pre-blow mold 22.To facilitate the removal of the parison, neck mold 39 is brought intoengagement with the exposed neck portion of the parison. For example, ifa split neck mold is employed, it should be held open to permit entry ofthe parison, and thereafter closed. Blow core 30 is then retracted frompre-blow mold 22, which may be split to release preformed parison 29.Upon release, core 30 with parison 29 thereon engaged by neck mold 39,returns to the position illustrated in FIG. 1 and depicted in phantom inFIG. 2B.

Upon completion of the above transfer, mold assembly 21 is laterallyshifted so as to juxtapose finish mold 23 and blow core 30 while at thesame time aligning pre-blow mold 22 and core 15, as described earlierand depicted in FIG. 2B. The blow cores are then received within therespective molds, and parison 29 is axially extended into contact withthe inner surface of finish mold 23, as represented in phantom, by theadvancement of mandrel 32 by means of push rod 34. The same effect canbe achieved, even in pre-blow mold 22, by the use of a blow core whichemploys a segmented mandrel having an axially extensible anteriorportion such as is disclosed in my copending U.S. application Ser. No.338,362, filed Mar. 5, 1973. This step conveniently stretches theparison longitudinally before final blowing, without the problems notedheretofore, and thereby produces orientation in the axial direction aswell as the orientation subsequently produced by blowing. It can be seenthat frictional discontinuities are avoided and that the temperature ofthe parison, in its original and pre-blown states may be properlycontrolled by contact with the respective molds.

After the completion of axial extension, the parison is fully expandedto conform to the configuration of finish mold 23 to form the finalobject 41 which, in the embodiment illustrated herein, is a bottle. Fullexpansion is accomplished by supplying fluid under pressure throughpassageway 38 into the interior of axially extended parison 29. Afterfull expansion is completed, blow core 30 and finish mold 23 containingfinal object 41 are separated in the same fashion described earlier withreference to blow core 15 and pre-blow mold 22, and blow core 30 ispositioned as shown in phantom, in FIG. 2A. Referring further to FIG.2A, mold assembly 21 is shifted laterally, and finish mold 23 ispositioned for removal of final object 41, which is by then cooledsufficiently for that purpose.

Removal is conducted in various ways depending upon the configuration ofthe finish mold. In the embodiment illustrated herein, finish mold 23possesses a constricted opening, and is longitudinally split into twosections labeled 42 and 43, which may reciprocate in and out ofcommunication along connecting means 44, by an actuating means, notshown, such as, for example, a hydraulic cylinder. Thus, in FIG. 2A,sections 42 and 43 are parted an amount sufficient to permit the escapeof object 41 as illustrated in phantom, and object 41 is then easilyremoved and may, for example, be placed on a carrier assembly 45,comprising a platform 46 which suports an appropriately dimensionedtransfer finger 47 connected to a source of fluid by line 48, which isplaced into the opening located in the neck of object 41, such as thatwhich is disclosed in my U.S. Pat. No. 3,587,133.

In a further embodiment disclosed in the aforementioned U.S. Patent anddepicted in FIG. 8, carrier assembly 45' comprises a rotary platform 46'which carries a plurality of transfer fingers 47' which are arranged toindex from position to a position of final removal of objects 41'. Thisarrangement is particularly useful with objects which, though removablefrom the finish mold, are insufficiently cooled to be handleable.

Yet a further modification of the removal step is contemplated, whereina plurality of finish molds is employed which, though capable of lateralreciprocation in the same manner as finish mold 23 in FIG. 1, areseparable from pre-blow molds and are carried by an indexing device toprovide a longer residence time of the final object in the mold. Theindexing device may be any device which is capable of conveying thefinish molds in and out of position in the mold assembly. One suchdevice is illustrated in FIG. 9, wherein a rotary indexing carousel 49is shown carrying four finish molds 23' on extensible connecting arms 51which radiate from a hub member 50. Connecting arms 51 are reciprocableto provide the lateral movement for the finish molds, and may beproximally enlarged as illustrated to house a reciprocating means, suchas, for example, a hydraulic cylinder. Naturally, other means ofreciprocation which are known in the art would be suitable herein, andthe invention is not limited to hydraulic power.

In operation, carousel 49 indexes a mold 23' into position adjacentpre-blow mold 22. Mold 23' is coupled thereto by a coupling means, notshow, and extensible connecting arm 51 permits it to reciprocate inconjunction therewith. Mold 23' is thus brought together with core 30.Upon finally expanding the parison and disengaging from core 30, mold23' bearing object 41' is then indexed out of alignment with core 30 andmoved in a counter-clockwise direction, in accordance with the figure,and the next empty mold takes its place. The mold travels to theposition it assumes just before being re-coupled with pre-blow mold 22,at which point, object 41' is removed.

Removal is conducted in the same manner as with finish mold 23, as themolds of this embodiment are likewise separable into sections 42' and43', respectively, which are reciprocable in and out of contact uponalignment means 44. Actuating means, not shown, for the opening andclosing of mold 23' may comprise suitably placed cams, or hydrauliccylinders, as is customary for this type of device.

It is considered that the above embodiment could be employed inconjunction with the embodiment of FIG. 8 to provide, where desirable,an extended cooling time for the final object. Other devices which areknown to those skilled in the art may be employed in place of theaforenoted carrier assembly within the scope of this invention.

Though a method and apparatus have been described above with referenceto the preparation of single-layered parisons by injection or otherpressure molding in a parison die, and exposing said parisonsimmediately to the further steps of the process, a wide variety ofmodifications may be employed within the scope of this invention.

In one modification, the parison may be formed earlier at a time andlocation of its own, and stored before being formed into the finalobject. In addition to injection molding, numerous methods are knownthat may be employed to provide thermoplastics in the shape of aparison, such as tube extrusion with welding of one open end, dipping,deposition, thermoforming and the like. Thus, the previously producedparison may be transported to and placed upon a first blow core whichcooperates with a heating means to raise the temperature of the parisonsufficiently to enable it to undergo deformation. An apparatus of thistype is shown in FIG. 3, wherein dispenser 54 contains a quantity ofpreviously formed parisons 55 which are singly released upon engagementwith core member 56 by known means. Core member 56 substantiallyresembles blow core 15 in FIG. 1, with the feature that mandrel 57contains heating means 58 which may be an electric cartridge heater or apassage containing heating fluid maintained at an elevated temperatureby external heating means, not shown.

In addition to heated core member 56, a heating mold 59 may be employedto heat the outer surface of the parison when in engagement therewith.Mold 59 is located in the same horizontal plane occupied by dispenser 54and in spaced relation thereto, and, incidentally, retains the sameposition occupied by parison die 10 in FIG. 1. Core member 56 is adaptedto reciprocate laterally as well as axially, so as to alternately alignwith both structures. Heating mold 59, like core member 56, may possesselectric or fluid heaters 60 suitably placed to heat its inner walls fortransmitting heat to a parison placed into contact therewith by knownmeans. Conventional temperature regulators are used to control theheating means of core 57 and mold 59 individually. Core member 56 andheating mold 59 may be held together under enough pressure with aparison between them to assure that the parison is uniformly brought totemperature for subsequent deformation.

As noted earlier, the method and apparatus of this invention are easilyadapted for the preparation of composite and lined hollow objects as,for example, described in my U.S. Pat. No. 3,737,259. In the embodimentshown in FIG. 4, dispenser 54 is shown in horizontal alignment with aparison die 10', and both are in vertical alignment with platform 62carrying diametrically opposed blow cores 15' and 15", respectively, inall respects structurally conforming with first blow core 15 in FIG. 1.Platform 62 is adapted to reciprocate cores 15' and 15" in the mannershown diagrammatically in FIG. 4 into and out of engagement withdispenser 54 and die 10', on vertical rod 63, and is rotatablyreciprocable by an actuating means, not shown, which cooperates withrack-and-pinion linkage 64. Thus, in operation, platform 62 is raised tosimultaneously engage dispenser 54 and die 10', and core 15' receives apreform 55' which may be either a parison or a liner. Platform 62 isthen lowered and, after transfer of the hot parison to pre-blow mold 22,it is rotated 180°. Core 15' carrying a preform 55' is thus brought intoengagement with die 10'. If preform 55' is a liner, injectiontherearound of a subsequent layer takes place next. If pre-form 55' is aparison, die 10' serves merely to heat same to forming temperature, asabove. As shown in FIG. 4, platform 62 and die 10' are spatiallydisposed to facilitate transfer of the composite or lined parison fromcore 15' to mold 22 in accordance with the embodiment illustrated inFIGS. 2A and 2B. The details of this apparatus are disclosed in my U.S.Pat. No. 3,737,259, issued June 5, 1973, and are incorporated herein byreference.

It is understood that, whenever previously produced parisons areemployed, as for example in the embodiment according to FIG. 3, suchparisons may be provided with an inside coating or liner, and, as such,may be multi-layered.

An alternate embodiment for the preparation of composite or linedobjects is shown in FIGS. 5A and 5B. In this embodiment, the apparatusis operative in the inverse direction from that of FIGS. 1 - 2B. Theapparatus comprises a liner or parison dispenser 61 which is adapted toperiodically release a parison or liner 65 into carrier assembly 66.Carrier assembly 66, which comprises a receptacle, is connected topre-blow mold 22 by connecting member 67 in the same manner that member24 connects molds 22 and 23. The entire assembly 21' is laterallyreciprocable and, upon the placement of a liner or parison in carrierassembly 66, is moved so as to align carrier assembly 66 with blow core15. Blow core 15 and parison die 10 are related here in the same mannerdisclosed in FIGS. 1 - 2B, except that, whenever a previously madeparison is used, die 10 is a heating die as shown in FIG. 3, and, ofcourse, is not in engagement with an injection nozzle. At the injectionor heating step, as the case may be, shown in FIG. 5B, blow core,carrier assembly and die are in alignment.

In order to inject or heat the parison, blow core 15 is brought intoengagement with carrier assembly 66 to receive parison or liner 65. Theparison or liner 65 may also be engaged by a neck mold 70 in the mannerdisclosed with reference to neck mold 39, above. Upon receiving theparison or liner 65, core 15 continues its movement to engage die 10 tobe heated, or surrounded by another, injected plastic, as the case maybe. Carrier assembly 66 is divided into sections 68 and 69 which areadapted to part in response to an actuating means, not shown, which isconnected to section 68 at 71. Thus, as shown in FIG. 5B, carrierassembly 66 parts to allow core 15 with the parison or liner thereon, toextend into die 10. By suitable linking of the movements of core 15 andsections 68 and 69, the core may thus be moved without pausing to awaitseparation of sections 68 and 69.

After injection or heating is completed, core 15 and die 10 areseparated and core 15 returns to the position depicted in FIG. 5A.Sections 68 and 69 of carrier assembly 66 are reunited and assembly 21'is laterally reciprocated whereby carrier assembly 66 and dispenser 61are juxtaposed while pre-blow mold 22 is readied to receive core 15bearing composite parison 72. Upon placement of composite 72 in mold 22,the cycle is carried forward as, for example, described in connectionwith FIGS. 1, 2A and 2B.

In addition to modifications such as the above, relating to the type ofparison provided and the manner of its provision, there is contemplateda further modification dealing with the control of the parison duringextension and blowing. Specifically, the embodiment illustrated in FIGS.6 and 7A - 7C comprises a series of individually temperature controlledmolds coacting with a series of mandrels whose axial movement isindividually and independently regulated.

FIG. 6 is a schematic representation of the apparatus of thisembodiment. The structures represented herein are similar to theapparatus of FIG. 1, but such similarity should not be construed aslimitative, as a wide variety of cores, molds and means to move them maybe employed within the scope of this invention. Thus, blow core 73 is inall respects representative of blow core 15, and may possess all of thefeatures of the latter. Mold assembly 74 resembles assembly 21 in themovement and general appearance, but possesses certain notabledifferences. The individual molds labeled 75 - 78, respectively,resemble molds 22 and 23 but are provided with electric heaters and/orfluid passages respectively labeled 79 - 82, which are connected, in amanner not shown, to electric current and/or fluid circulating means.Individual electrical resistance or fluid temperature control means 83 -86 are schematically shown to indicate that the temperature within molds75 - 78 is individually controllable. Assembly 74 is adapted for lateralreciprocation in the same manner as assembly 21 in FIG. 1.

Core assembly 87 is generally equivalent to a plurality of cores such ascore 30 of FIG. 1. In this embodiment, the cores are situated in commonplaten 88, and are likewise axially reciprocable. Individual cores 89 -91 differ from core 15 by the provision of individual speed controls,not shown, in conjunction with actuating means 92 - 94, therebypermitting independent variation of the speed of axial extensionemployed with a particular core.

The operation of the method in accordance with this embodiment issimilar to that depicted in FIGS. 2A and 2B, and is illustrated in FIGS.7A - 7C. Thus, in FIG. 7A, core 73 bearing parison 95 enters mold 75,while, at the same time, cores 89 - 91 bearing parisons 96 - 98, enterrespective molds 76 - 78, and extension and/or expansion therein isconducted, as depicted in FIG. 7B, at a predetermined rate determined bythe pre-selected speed of mandrels 89 - 91, and at a pre-determinedtemperature obtained by controlling the temperature of molds 76 - 78accordingly. Upon completion of expansion, the cores are separated fromthe parisons and separated from the respective molds, as shown in FIG.7C, and mold assembly 74 is laterally transferred to permit the removalof fully formed object 98, and the transfer of parisons 95 - 97 frommolds 75 - 77 to cores 89 - 91 respectively. Assembly 74 is then shiftedinto the position shown in FIG. 7A to receive another parison from core73.

The method and apparatus disclosed above are succeptible to the changesand modifications disclosed with respect to the embodiment of FIG. 1,and all of such changes are encompassed herein.

The above method enables the adaptation of the conditions of deformationto the particular material being processed while retaining the operatingeconomy of a conventional blow-molding process. The above method makesit possible to carry out the steps of axial and/or radial orientation atthe temperatures that are suitable to produce the best properties in agiven plastic. Thus, a cooling or heating dwell may be introduced beforeaxially extending the parison. Alternatively, the parison orpredetermined regions thereof may be heated to alter the degree oforientation in such regions. Most importantly, though the parisons areconditioned and their deformation determined individually for theseveral steps that the processing for any given plastic may demand, theoverall operating cycle is not lengthened, as the various operations areconducted simultaneously due to the synchronous operations of the blowcores and the mold assembly.

The finished object of the present invention is likewise characterizedby many advantages. In particular, the wide wall thereof arecontrollably oriented in the axial, radial and tangential directionswithout longitudinal discontinuities or thinning. Furthermore, thearticle of the present invention has substantially uniform wallthickness. The uniform wall thickness in an article so oriented ishighly advantageous.

Naturally, the present invention is quite versatile and a wide varietyof articles of varying configurations may be readily prepared. Ifdesired, the present invention may be performed on a continuous basis orintermittently. For example, as noted above, the process may beinterrupted at any convenient stage, the product stored or shipped toanother location and the process subsequently completed, such asshipping the molded parison from one location to another.

This invention may be embodied in other forms or carried out in otherways without departing from the spirit or essential characteristicsthereof. The present embodiment is therefore to be considered as in allrespects illustrative and not restrictive, the scope of the inventionbeing indicated by the appended claims, and all changes which comewithin the meaning and range of equivalency are intended to be embracedtherein. What is claimed is:

1. An apparatus for the preparation of parisons comprised of more thanone layer of moldable organic plastic material which comprises: adispenser containing a quantity of parison liners; a core having an axisand being in spaced relation to said dispenser, and further beingoperable to receive a parison liner from said dispenser; a parison diein axial alignment with said core and engageable therewith, said parisondie being operable to inject plastic around said core and liner; andmeans for conveying a parison liner from said dispenser into axialalignment with said core and said parison die, wherein said core ismoved along its axis to receive said parison liner from said means thento engage said parison die by directionally uninterrupted relative axialmovement, and means to blow mold the composite liner and injectionmolded layer.
 2. An apparatus according to claim 1 wherein said core isaxially moveable, and wherein said core is operable to receive saidparison liner and engage said parison die in a directionallyuninterrupted axial movement.
 3. An apparatus according to claim 2wherein said conveying means is engageable with said core.
 4. Anapparatus according to claim 3 wherein said conveying means is laterallyreciprocable into and out of alignment with said core and parison die.5. An apparatus according to claim 4 wherein said conveying means isseparable into two sections upon engagement with said core.
 6. Anapparatus according to claim 1 including a neck mold associated withsaid core operable to engage said liner on said core.
 7. An apparatusaccording to claim 6 wherein said neck mold is separable into twosections.
 8. An apparatus according to claim 2 wherein said parison dieis in axial alignment with said core beneath said core, said conveyingmeans is laterally reciprocable into and out of alignment between saidparison die and core, and wherein said core is engageable with both saidconveying means and parison die in an uninterrupted downward movement.9. The apparatus of claim 1 wherein said conveying means comprises acarrier assembly juxtaposed with said dispenser and laterallyreciprocable into alignment between said core and parison die.
 10. Theapparatus of claim 9 wherein said carrier assembly comprises areceptacle which is separable into at least two sections and means forseparating and uniting said sections.